Significantly enhanced electrical properties in CaBi2Nb2O9-based high-temperature piezoelectric ceramics

A synergetic effect of Li/Nd at the A site and W/Mn at the B site co-substitution on electrical properties of calcium bismuth niobate (CaBi2Nb2O9, CBNO)-based ceramics is proposed in this paper. CBNO primarily shows mixed p-type and ionic conduction due to a trace of oxygen vacancies (V-O(center dot center dot)). Both bulk resistivity (rho (b)) and activity energy (E-a) for conduction are dramatically increased by the co-substitution in Ca-0.92(Li1/2Nd1/2)(0.08)Bi2Nb2-x(W3/4Mn1/4)(x)O-9 [CBNO-LN-x(WM), x=0-0.02]. Consequently, the modified compositions almost show an intrinsic conducting mechanism due to a significant suppression of the V-O(center dot center dot) concentration. Furthermore, the synergetic effect of Li/Nd at the A site and W/Mn at the B site greatly improves the piezoelectricity coefficient (d(33)), which is up to similar to 21.1 pC/N in the optimized composition [CBNO-LN-10(WM)]. This combined with a high Curie temperature (T-C=similar to 946 degrees C) and high resistivity indicates that CBNO-LN-10(WM) is a good promising material in high-temperature piezoelectric applications.